It is known and is usual for both disk and drum brakes to be provided with devices, generally known as wear indicators, which can detect the state of wear of the friction linings. Existing devices differ in their operating principle and in their structural configuration; in motor-vehicle disk brakes, electrical wear indicators which use a sensor associated with a pad of the brake caliper are widely used. These indicators transmit the signal, which comes from the sensor and is indicative of the wear of the pad, through an electrical wire terminating in a connector which in turn is connected, by means of a corresponding electrical contact element and another electrical wire, to an indicator disposed, for example, on the dashboard of the motor vehicle.
During the assembly of the caliper, particularly of a caliper intended for commercial vehicles, the connector is connected to the caliper purely indirectly by means of the electrical wire which extends from the sensor incorporated in the pad; this constitutes an inconvenience for the assembler and a risk to the integrity of the wire. Moreover, there is a similar disadvantage during the mounting of the caliper on the hub-carrier of a vehicle wheel, since the electrical contact element which is intended to be connected to the connector, usually by a plug-in connection, is suspended on the wire extending from inside the vehicle, without a precise position. It is only upon completion of the mounting that the contact element is inserted in the connector and the connector and/or the wires which extend from it are secured to a fixed part of the structure, for example, to the caliper, by suitable fixing systems.